An accessory gear box of an aircraft engine is mounted on an engine case. The accessory gear box serves to distribute a driving force taken out of an engine core to various auxiliary devices. In general, the accessory gear box extends in the circumferential direction of the engine case and is mounted on the engine case by a plurality of mount mechanisms arranged at multiple points in the circumferential direction of the engine case.
For example, Patent Literature 1 discloses a pair of mount mechanisms (namely, side hangers) disposed at both end portions of an accessory gear box. Each of the mount mechanisms incudes a first bracket fastened to an engine case, a second bracket fastened to the accessory gear box, and a link whose both end portions are coupled to the first bracket and to the second bracket by pins.